FADE AND WEAR CHARACTERISTICS OF A GLASS-FIBER-REINFORCED PHENOLIC FRICTION MATERIAL

The fade and wear characteristics of a glass-fiber-reinforced friction material were,studied using a Chase friction material testing machine. At low counterface temperatures, the friction material showed relatively high friction in the range 0.4-0.5. During fade tests, the coefficient of friction dropped to about 0.18 at 343-degrees-C. Re-conditioning the wear surface at the end of a fade test altered the frictional behavior during a subsequent fade test. The wear tests showed that the specific weight loss per unit load and sliding distance decreases with increasing applied load and speed, but increases with increasing bulk drum temperature. At high temperatures, thermochemical degradation and fiber pull-out appear to contribute to higher specific wear rate. The worn surfaces of the specimens were observed by scanning electron microscopy and analyzed by energy-dispersive X-ray analysis. The results were consistent with low friction coefficients due to film formation on the worn surfaces of glass fiber at high temperatures. This film could be removed at lower temperatures by either sliding (application) or by sanding.